1. emacs profile
2. PS1
3. add current user(sk) to sudoers, and set not need password when use sudo:
   modify /etc/sudoers in root :
	chmod +w /etc/sudoers
	add :
		sk ALL=(ALL) NOPASSWD:ALL
	or admin group not need password: ??
		%admin ALL=(ALL) NOPASSWD:ALL
	chmod -w /etc/sudoers
